Cannot add VMware hosts to vSphere Center due to Datastore error

[AlphaAdmin]

Hello, this is a brand new ESXi 5.5 U2 install with 3 hosts (HP DL380 Gen8) and one SAS Storage (HP MSA 2040). I installed ESXi on all hosts, deployed vCSA 5.5, and tried to add the hosts. The first host is added fine but the other two give an error:

Datastore <datastore> conflicts with an existing datastore in the datacenter that has the same URL (ds:///vmfs/volumes/<volume>) but is backed by different physical storage.

I searched online and tried a few things including unmounting the datastore, trying to delete the datastore in order to re-add it (I couldn't delete it), and re-installing ESXi from scratch. I also moved vCSA around and tried adding the hosts in different order. No luck, the problem remains.

I connected to each host via SSH. I run esxcfg-scsidevs -m and for all 3 hosts I got:
/vmfs/devices/disks/naa.600c0ff0001dbcdc2ebb165401000000:1 -> 52d350bd-499e482f-d0da-a0d3c1048ac8
I then run ls -lrth /vmfs/devices/disks | grep -i naa and for all 3 hosts I got:
vml.0200010000600c0ff0001dbcdc2ebb1654010000004d5341203230 -> naa.600c0ff0001dbcdc2ebb165401000000
vml.0200010000600c0ff0001dbcdc2ebb1654010000004d5341203230:1 -> naa.600c0ff0001dbcdc2ebb165401000000:1

The above looks correct so I am basically stuck. Any ideas? Many thanks.

[vuzzini]

The quick solution would be to physically disconnect the storage cables from affected ESXi host, reboot the host. Once the host comes back online, reconnect them to vCenter Server and then connect the storage cables back and perform a rescan on the cluster.

[AlphaAdmin]

Hello and thanks for the reply.

The good news is that you are genius and this worked!

I could connect the hosts to vCSA.

The bad news is that after the hosts connected, I rebooted them and got the same problem.

Obviously I cannot plug & unplug cables every time this happens.

Is there a more reliable solution?

Thanks

[vuzzini]

Hello AlphaAdmin,

I understand from your first note that you tried to delete the datastore but it did not work. Could you please check whether there are any templates or virtual machine is referencing a resource on the datastore in question. Ensure no ISO's are mounted to a virtual machine from the datastore in question.

Then to delete the VMFS datastore: take a putty to ESXi host, run the command partedUtil mklabel "/vmfs/devices/disks/<naa.id>" msdos.

Rescan the hosts and try to add the affected host to vCenter server.

[AlphaAdmin]

Thanks for the reply.

This is brand new installation and there are no VMs, just vCSA.

Regardless, I had already started a clean install by the time I saw your answer.

I actually did a combination of a clean install and the suggestion to unplug the DAS.

This is what I did:

- Unplugged all cables from the DAS

- Wiped out & re-installed ESXi on all hosts

- Connected DAS to Host1, connected via vSphere client and deployed vCSA

- Configured vCSA

- Added Host1 to vCSA

- Connected DAS to Host2 and connected Host2 to vCSA

- Connected DAS to Host3 and connected Host3 to vCSA

All hosts connect properly and they reconnect after reboots.

Thanks

Christos